d464e84eed
We can build one skb and let it be cloned in netlink.
This is much faster, and use less memory (all clones will
share the same skb->head)
Tested:
time perf record (for f in `seq 1 3000` ; do ip netns add tast$f; done)
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 4.110 MB perf.data (~179584 samples) ]
real 0m24.227s # instead of 0m52.554s
user 0m0.329s
sys 0m23.753s # instead of 0m51.375s
14.77% ip [kernel.kallsyms] [k] __ip6addrlbl_add
14.56% ip [kernel.kallsyms] [k] netlink_broadcast_filtered
11.65% ip [kernel.kallsyms] [k] netlink_has_listeners
6.19% ip [kernel.kallsyms] [k] _raw_spin_lock_irqsave
5.66% ip [kernel.kallsyms] [k] kobject_uevent_env
4.97% ip [kernel.kallsyms] [k] memset_erms
4.67% ip [kernel.kallsyms] [k] refcount_sub_and_test
4.41% ip [kernel.kallsyms] [k] _raw_read_lock
3.59% ip [kernel.kallsyms] [k] refcount_inc_not_zero
3.13% ip [kernel.kallsyms] [k] _raw_spin_unlock_irqrestore
1.55% ip [kernel.kallsyms] [k] __wake_up
1.20% ip [kernel.kallsyms] [k] strlen
1.03% ip [kernel.kallsyms] [k] __wake_up_common
0.93% ip [kernel.kallsyms] [k] consume_skb
0.92% ip [kernel.kallsyms] [k] netlink_trim
0.87% ip [kernel.kallsyms] [k] insert_header
0.63% ip [kernel.kallsyms] [k] unmap_page_range
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.